std::basic_string<CharT,Traits,Allocator>::operator basic_string_view
From cppreference.com
< cpp | string | basic string
operator std::basic_string_view<CharT, Traits>()constnoexcept; | (since C++17) (constexpr since C++20) | |
Returns a std::basic_string_view, constructed as if by std::basic_string_view<CharT, Traits>(data(), size()).
Contents |
[edit]Parameters
(none)
[edit]Return value
A string view representing the entire contents of the string.
[edit]Notes
It is the programmer's responsibility to ensure that the resulting string view does not outlive the string.
std::string get_string();int f(std::string_view sv); int x = f(get_string());// OKstd::string_view sv = get_string();// Bad: holds a dangling pointer
[edit]Example
Run this code
#include <iostream>#include <string>#include <string_view> void show_wstring_size(std::wstring_view wcstr_v){std::cout<< wcstr_v.size()<<" code points\n";} int main(){std::string cppstr ="ラーメン";// narrow stringstd::wstring wcstr = L"ラーメン";// wide string // Implicit conversion from string to string_view// via std::string::operator string_view:std::string_view cppstr_v = cppstr; std::cout<< cppstr_v <<'\n'<< cppstr_v.size()<<" code units\n"; // Implicit conversion from wstring to wstring_view// via std::wstring::operator wstring_view: show_wstring_size(wcstr);}
Output:
ラーメン 12 code units 4 code points
[edit]See also
constructs a basic_string_view(public member function of std::basic_string_view<CharT,Traits>) |
